sctp: fix overrun in sctp_diag_dump_one()

The function sctp_diag_dump_one() currently performs a memcpy()
of 64 bytes from a 16 byte field into another 16 byte field. Fix
by using correct size, use sizeof to obtain correct size instead
of using a hard-coded constant.

Fixes: 8f840e47 ("sctp: add the sctp_diag.c file")
Signed-off-by: Lance Richardson <lrichard@redhat.com>
Reviewed-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/sctp/sctp_diag.c

@@ -424,11 +424,13 @@ static int sctp_diag_dump_one(struct sk_buff *in_skb,
 		paddr.v4.sin_family = AF_INET;
 	} else {
 		laddr.v6.sin6_port = req->id.idiag_sport;
-		memcpy(&laddr.v6.sin6_addr, req->id.idiag_src, 64);
+		memcpy(&laddr.v6.sin6_addr, req->id.idiag_src,
+		       sizeof(laddr.v6.sin6_addr));
 		laddr.v6.sin6_family = AF_INET6;
 
 		paddr.v6.sin6_port = req->id.idiag_dport;
-		memcpy(&paddr.v6.sin6_addr, req->id.idiag_dst, 64);
+		memcpy(&paddr.v6.sin6_addr, req->id.idiag_dst,
+		       sizeof(paddr.v6.sin6_addr));
 		paddr.v6.sin6_family = AF_INET6;
 	}